The present invention relates to a system for measuring the productivity of an excavator used in open pit coal mining and, more particularly, to a system that measures and stores various excavator parameters, then analyzes the stored data in order to determine the walking, digging, delay or special activity time spent by the excavator. The data is further analyzed and summarized to provide production reports on a shift or daily basis useful in measuring the efficiency of the excavator, and to assist in the planning of the mining operation.
It is estimated that one typical walking dragline excavator, having a bucket capacity of 50 cubic yards, will strip about 3.6 million tons of coal in a year. If the coal sells for $3 per ton, and if the productivity of that excavator can be increased by 5%, the mine operation will realize more than one-half million dollars of additional income during the year. One approach to measuring the productivity of an excavator is to calculate the amount of coal that has been mined based on either estimating or measuring the volume of coal that has been mined. This method of calculating productivity is not accurate enough to measure small changes in productivity.
Another approach for measuring the productivity of an excavator recording the swing action of the boom on a strip chart recorder. When the excavator is mining, a typical digging cycle consists of digging to fill the bucket with coal overburden, lifting the bucket and swinging the boom so that the bucket is over a dump pile, dumping load and then swinging the boom back to begin another digging cycle. If it is assumed that the bucket load is constant during each swing cycle, then the number of swing cycles that occurred during a shift or a day would be indicative of dragline productivity. This approach for measuring productivity is subject to considerable error because it does not take into account how the varying load in each bucket, and because each swing cycle does not necessarily result in a bucket of overburden being removed. For example, the boom may be swinging because the excavator is being used to build a path for itself in the mine.
It is, therefore, a primary object of this invention to provide a system that accurately measures the productivity of an excavator.
It is a further object of this invention to measure and record various parameters of an excavator for later analysis by a computer.
Another object of this invention is to provide reports to a mine supervisor summarizing the activities of an excavator.
And yet another object of this invention is to provide a mine supervisor with a report analyzing the activities of an excavator so that the mining supervisor can plan more efficient use of the excavator.